planter box maintenance for homeowners...planter box: a regulated above-ground rain garden, it...
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Overmulching. The ponding depth is
eliminated when too much mulch is added.
Instead of soaking into the planter’s soil, the
water exits through the overflow during small
storm events.
Department of Environmental Services 2100 Clarendon Blvd, Suite 705, Arlington, VA 22201
Planter Box: A regulated above-ground rain garden, it receives water from a downspout, is
planted primarily with native plants, and has an underdrain. The ponding water is soaked up by the
plants, or discharged through the underdrain within 48-72 hours following a rain event.
Planter Box Maintenance for Homeowners
The planter box on your property is required for stormwater management. Prior to submitting your
annual Stormwater Management Facility Operation and Maintenance Inspection Form, use this fact
sheet to review your planter box and ensure it is in compliance.
Common Planter Box Errors
If you notice these issues, correct them prior to submitting your form.
An “A+” Planter Box
Too few plants or the wrong type of plants. 80%
plant coverage is required, primarily by native species.
The use of seeds to plant the area is not acceptable. The
use of annuals and vegetables are also not permitted.
Specific, native species are required because they thrive
in the planter box environment and provide year-round
benefits.
This example has:
Adequate plant coverage by native plants.
Energy dissipater (the stones) is below the
downspout.
Correct mulch and ponding depths.
Grated cover on overflow.
Mulch has filled in the ponding
area to the top of the planter.
Mulch has filled in the ponding
area to the top of the overflow.
Too few plants
Wrong type of plants
Planter Box Design Criteria:
Arlington’s Stormwater Manual: A Guide to Stormwater
Requirements for Land Disturbing Activities in Arlington
County
Virginia DCR 2013 Design Specification No. 9 Bioretention,
version 2.0
Key Elements of a Planter Box
Energy Dissipater—Cobble or splash block prevents incoming water from eroding or damaging
nearby plants.
Mulch—An even depth of 2-3 inches of hardwood mulch extends across the entire surface.
Overflow—During large storm events rainwater fills the planter, enters the overflow, then exits
through the underdrain. Ensures excessive flows are properly directed, and do not overtop the
planter and run along the home’s foundation.
Ponding Depth—Maximum depth of water during a storm event, prior to entering the overflow.
Measured from top of overflow to mulch.
Soil Media—A specific sand, soil and organic matter blend. Nutrient-enriched top soil is not
permitted.
Structural Soundness—Planter box walls (concrete or wood/liner) must be free of cracks,
separation, settling, etc. Buckling walls, deteriorating box materials, tears in liner, and signs of
water damage are not acceptable.
Underdrain—Perforated pipe “buried” in the stone layer ensures proper drainage. Carries excess
water to the storm drain system or another location on your lot.
Acceptable Plant List:
Virginia DCR 2013 Design
Specification No. 9 Bioretention,
version 2.0—Table 9.6, Popular Native
Plant Materials for Bioretention